A New Meaning of "My Wife Will Be the Death of Me": Pulmonary Langerhans Cell Histiocytosis in a Secondhand Smoker

Abstract

INTRODUCTION: Pulmonary Langerhans cell histiocytosis (PLCH) is a cystic disease that makes up 3-5% of interstitial lung diseases. It is thought to be secondary to infiltration of Langerhans cells (CD1a positive histiocytes) in the lung leading to destruction of bronchiolar walls and parenchyma and the development of interstitial fibrosis and cysts with advanced disease. At least 90% of patients are current smokers. It mostly affects younger adults, with a peak at age 20-40 years. We present a case of PLCH in an elderly patient who quit smoking 13 years prior but had persistent exposure to secondhand smoke because his wife smoked.CASE PRESENTATION: A 70-year-old male former smoker with a history of emphysema and aortic abdominal aneurysm (AAA) presented for imaging abnormalities noted incidentally during surveillance for AAA. He was asymptomatic. He was noted to have ground-glass nodules measuring 1.3 cm. He was lost to follow-up until 3 years later when a repeat CT showed unchanged ground-glass opacity (GGO) with new cysts and extensive nodules associated with cavitation in the upper lobes bilaterally. Further progression was noted on CT Chest 3 months later with upper lobe predominant interstitial thickening with GGOs, tree-in-bud opacities and new cavitary solid and subsolid pulmonary nodules. Navigational bronchoscopy was performed for transbronchial biopsy of a nodule and bronchoalveolar lavage. Work-up for bacterial, viral, and fungal infections was negative. Biopsy showed zones of fibrosis containing smokers' macrophages and cells with folded and grooved nuclei highly suspicious for pulmonary Langerhans cells which stained positive for CD1a, confirming PLCH. He had a 43 pack-year history and quit 13 years prior but reported that his wife was an avid current smoker. He was counseled to avoid all exposure to tobacco smoke with regular monitoring on imaging.DISCUSSION: The natural history of PLCH is variable, ranging from spontaneous remission to end-stage fibrotic lung disease with continued smoking. Complications can include pneumothorax and pulmonary hypertension, which is independently associated with increased mortality. PLCH is a smoking-related interstitial lung disease and smoking cessation has been shown to resolve or stabilize disease in 62% of patients. While PLCH is typically seen in younger, current smokers, our case highlights the importance of maintaining a high index of suspicion for PLCH in upper lobe predominant cystic and nodular disease, even in an older patient who does not smoke as they may have continued exposure to secondhand smoke.CONCLUSIONS: Screening for exposure to secondhand smoke and stopping exposure is crucial to prevent high morbidity and poor quality of life in patients with PLCH